Electroplating of nickel



Patented Oct. 6, 1953 UNITED STATES ATE; OFFICE ELECTROPLATING F NICKEL No Drawing. Application September 16, 1950, Serial No. 185,316

Claims.

Our invention relates to improvements in the electrodeposition of nickel from aqueous acidic baths. It is particularly concerned with the utilization of mixtures of certain types of agents for the purpose of decreasing grain size and increasing the luster of the nickel plate or deposit, and it is especially concerned with the production of electrodeposits of brilliant, highly lustrous, ductile nickel plates.

We have discovered that the above highly desired results are achieved through the conjoint utilization, in the nickel plating bath, of one or more agents of the type exemplified in the following Table I (added as such or formed in situ in the bath), in conjunction with one or more agents of the type exemplified in the following Table II.

The agents of Table I are illustrative of the class of compounds, found to be useful in the practice of our present invention, in accordance with the formula where represents a compound of the quinoline series selected from the group consisting of quinoline, isoquinoline and C-methyl and ethyl homologues thereof; A is an anion of a Water-soluble acid; R is halogen, such as chlorine, bromine and iodine, but particularly chlorine and bromine; R is a member selected from the group consisting of halogen, nitro, methyl and fluoromethyl groups; Ar is a benzene or naphthalene radical; Z is hydrogen, methyl or ethyl, particularly hydrogen, and x and y are each zero to 2.

The anion represented by A can be any one of a number such as, for example, chlorine, br0- mine, iodine, sulfate, methosulfate, acetate, citrate, and tartrate. Particularly desirable are the compounds where A is bromine or chlorine.

As indicated, R is halogen, R can be halogen, nitro, methyl or fluoromethyl groups, and, as x and y can be zero, 1 or 2, the compounds can, for example, contain one or two nuclear halogen atoms in each of the heterocyclic nucleus and the benzene or naphthalene nucleus, or, where x and y are each zero, the aforesaid nuclei are unsubstituted. Excellent results are obtained with compounds Where :1: and y are zero; or where R is chlorine or bromine, R is ch10- rine, bromine or nitro, and m is zero and y is 1 or where a: is 1 and y is zero, or where both an and y are 1, and especially where Ar is a benzene radical.

Various of the types of quinolinium compounds, and isoquinolinium compounds utilized pursuant to our present invention can, individually, be represented by the following formulae:

Quinolinium Compounds Isoquinolinium Compounds In the said compounds, the letters A, R, R, Z and a and 1 have the foregoing significance. In all instances, the bonds leading from the radicals R, and R indicate that said radicals can be substituted at any of the positions of the ring of the quinoline or isoquinoline radical.

Of particular utility are N-benzyl-Z-methyl quinolinium chloride;

TABLE I Optimum No. Compound Cone, Grams/ iter 1 N-benzyl quinolinium chloride .01-.04 N-benzyl isoquinolinium chlorid 01-. 04 1 N-benzyl quinolinium'sulfat.-. .01-.04 N-(benzylQ-methyl quinolinium chor- 005-. 04

i e. N-benzyl-2,6-dimethyl quinolinium .005-. 04

bromide. N-benzyl-2-ch1oro quinolinium 01-. 04

chloride. N-benzyl-Z-bromo quinolinlum .01-.04

bromide. Ngiaizyl-fi-chloro quinolinium bro- .01-.04

e. N-benzyl-2,4-dimethyl quinolim'um .005-.04

chloride. N-benzyl-2,4-dichloro quinolinium .01-.04

chloride. N-bcnz -2,8-dimethyl quinolinium .01-.04

chloride. N-benzyl-5,8-dimethyl quinolinium .01-.04

chloride. N-benzyl-1,3-dimethyl iso quinolinium 005-. 04

chloride. Nigenzyl-s-methyl quinolinium chlor- 01-. 04

e. N-benzyl-3-chloro-2-methyl quino- .01-. 04

lin.1um chloride. N-benzyl-3-bromo-2-methyl quino- .01-. 04

linium bromide. N-benzyl-3-methyl isoquinolinium .005-.04

chloride. N--nitrobenzyl quinolinium bromide. .003-. 03 N-2,4-dinitrobenzyl isoquinolinium .003-.03

bromide. N-lii-chlorobenzyl quinolinium chlor- .002-. 02

1 e. N-a-methyl naphthalene quinolinium .003. 02

chloride. N-a-Illethyl naphthalene isoquino- .003. 02

linium chloride. m-trifiuoromethyl benzyl quinolinium 003-. 02

bromide. m-triiluormethyl benzyl isoquino- .003-. 02

linium chloride.

The agents of Table II are illustrative of the class of compounds which are employed in conjunction with the agents of Table I, in the practice of our invention. The agents of Table II, it will be noted, fall into the category of organic sulfonamides, sulfonimides and sulfonic acids. They have heretofore been used as brighteners in nickel plating baths as is disclosed in part, for example, in my prior Patents Nos. 2,191,813 and 2,466,677. In the practice of our present invention, a coaction takes place in the cathode film, the exact nature of which is unknown, involving the compounds of the type shown in Table I and the organic sulfur-containing 'brightener which produces the unusual and highly important results which are brought about in accordance with our invention. In this connection, it may be noted that the utilization alone of the agents or compounds of the type shown in Table I, or the utilization alone of the organic sulfur-containing brighteners gives no indication of the remarkably enhanced results which occur when both types of compounds are present in the bath, particularly when utilized in their optimum concentrations. is desirable to use mixtures of two or more of said sulfur-containing brighteners as, for example, o-benzoyl sulfimide and p-toluene sulfonamide; and allyl sulfonic acid and benzene sulfonamide.

In general, it

TABLE II Optimum Sulfur-Containing Brightencrs 00110.,

Grams/Liter 1. Benzene sulfonamide 0. 1-3 2. Toluene sulfonamides (oand p-) 0. 1-2 3. o-Benzoyl sulfimide 0. 1-2 4. N-Benzoyl benzene sulfonimide- 0. 1-1 5. p-Toluene sulfonchloramida 0. 1-1 6. p-Brom benzene sulfonamide 0. 1-1 7. 6-Ohlor o-benzoyl sulfimide 0. 1-1 8. m-Aldehydo benzene sulfonamide. 0. l-l 9. Sulfomethyl benzene sulionamide 0. 1-0 10. Benzene sulfonamide m-carboxylic amide. 0. l-3 11. 7-Aldehydo o-benzoyl suliimide 0.1-3 12. N-Acetyl benzene sulfonimide..- 0. l-2 13. Methoxy benzene sulfonamides.. 01-1 14. Hydroxymethyl benzene sulfonamid 0. 1-2 15. Vinyl sulfonamide 4-12 16. Allyl sulfonamide 4-12 17. Bezene sulfonic acids (mo o-, di-, an 1-15 18. p-Brom benzene sulfonic acid 3-6 19. Benzaldehyde sulfonic acids (0, m, 2-6 20. Diphenyl sulfone sulfonic acid 1-8 21. Naphthalene sulfonic acids tri-) l-8 22. Benzene sulfohydroxamic a 1-5 23. p-Ohlor benzene snlionic acid 1-15 24. Diphenyl sulfonic acid 1-5 25. m-Diphenyl benzene sulfonic acid 1-4 20. 2-Ohloro-5-sulfobenza1dehyde l-5 27. m-Benzene disulfonamide. 0. 5-1 28. Allyl sulfonic acid 4-12 It will be understood that said sulfonic brighteners may be utilized in their acid form or in the form of salts as, for example, nickel, sodium, potassium or other salts. Especially satisfactory, for use in the practice of our present invention, are the compounds of Table II corresponding to numbers 1, 2, 3; 18, 19, 21 and 28, the latter particularly in the form of their nickel salts. Where the term sulfonic acids is used herein and in the claims, it will be understood that the salts thereof are likewise included.

The compounds of Table II, used alone, produce reasonably bright deposits on buffed metals such as buifed brass. However, at least in the ordinary case, they do not accomplish the same results on steel polished with emery or on matte (but unburnt) copper plate of 0.0003"- 0.0005 thickness but, rather, generally yield plates of somewhat dull and gray appearance in these cases. The compounds of Table I, in the usual case, when used alone, give a different type of plate than that produced by the compounds of Table II. The plates produced with the compounds of Table I alone are fine grained and cloudy at very low concentrations, and are rather dark, brittle, easily stained and have poor adherence characteristics at higher concentrations. If, however, the two different types of compounds represented in Tables I and II are used together in the baths, as we have indicated above, brilliant mirror-like, adherent and ductile deposits are obtained even over matte surfaces.

Only small proportions of the compounds, or mixtures thereof, of Table I are necessary to achieve the aforesaid results. Generally, proportions in the range of about 0.003 gram/liter to about 0.04 grams/ liter of any of the compounds or mixtures thereof will be most eifective in the usual case. Even in the case of the less effective ones of the compounds, it is rarely necessary to exceed about 0.06 to 0.08 grams/liter. As a general rule, the optimum concentration of the compounds will be found to fall within the range of about 0.003 to about 0.04 grams/liter.

The compounds of Table II are likewise used in small proportions, in conjunction with the compounds of Table I, amounts of the order of about 0.1 gram/liter to 2 or 3 grams/liter being effective in the usual case. Higher proportions, up to saturation, can, however, be utilized. Ordinarily, it is unnecessary to exceed about 0.5%.

The optimum concentration of the compounds of Tables I and II in any specific instance may readily be determined 'by simple test in the light of the particular nickel bath utilized, its temperature, its pH, etc.

The aqueous nickel plating baths may be of various types but, in all cases, they are acidic in character. The preferred baths are of the socalled acidic grey type which are capable of producing thick, adherent, ductile deposits, those of the Watts type or modifications thereof being What we claim as new and desire to protect by Letters Patent of the United States is:

1. A bath for the electrodeposition of bright nickel comprising an aqueous acidic solution of a material selected from the group consisting of nickel chloride, nickel sulfate, nickel fluoborate, a mixture of nickel chloride and nickel sulfate, a mixture of nickel fluoborate and nickel chloride, a mixture of nickel fluoborate and nickel sulfate, and a mixture of nickel sulfate, nickel chloride and nickel fluoborate, said bath also containing, in solution, not more than about 1.5% of at least one brightener selected from the group consisting of organic sulfonamides, sulfonimides, and

particularly d s a T e ic l sal s may ml5 sulfonic acids, and, in addition, about 0.003 to prise nickel chloride, nickel sulfate, nickel fluO- 0.08 gram per liter of a bath-soluble compound borate, nickel sulfamate, or other nickel salts or in accordance with the formula mixtures of any two or more of said nickel salts, preferably in conjunction with bufiermaterials CH:N A as, for example, boric acid. We prefer to utilize n boric acid in the bath as it is, in general, the best cathode film buffer. Other bufiers of acidic character may, however, be employed as, for ex- Where ample, formic acid, citric acid, fluo'boric acid, and the like, and such may be used either in place of 35 i N or in conjunction with boric acid. For optimum results, the concentration of the boric acid or its represents a compound f t quinoline series equivalent should be above grams per liter, selected from the group consisting of quinoline, especially in baths operated at somewhat elevated isoquinonne and C methy1 and ethyl homologues temperatures- The baths may also Contain 53%) thereof, A is an anion of a water-soluble acid, R ous supplemental agents such as anti-pitting is halogen, is a member selected from t agents and thelikegroup consisting of halogen, nitro, methyl and The baths can be operated at temperatures fiuoromethyl groups, and at and y are each Zero ranging from about room temperature to almost to boiling but, in general, the preferred temperature A bath in accordance with claim 1 wherein 15 in the range of about degrees to A is a member selected from the group consistgrees In general, the baths can be Operated ing of chlorine and bromine, and :c and y are each at pH values ranging from about 2 to about 5.5 zero but, in the ordinary case, the preferred pH values A bath in accordance t claim 1, h i are from 2.5 to 4.8. The cathode current density .10 is 5 nitro group, A is a member Selected frgm ranges are quite Variable a range of about 5 to the group consisting of chlorine and bromine, .1: several hundred amperes per square foot being is Zero andyis ufiilizablev the Optimum depending upon agita 4-. A bath for the electrodeposition of bright 111011, temperature, and concentration and type of nickel. comprising an aqueou acidic solution of nickel salts utilized in the bath. A good Working t m l ted from the group consisting of range is about 20 to about amperes per squ nickel chloride, nickel sulfate, nickel fluoborate, foot. In Table III, we list preferred embo a mixture of nickel chloride and nickel sulfate, 0f the bath COmIIOSilJiODS- a mixture of nickel fluoborate and nickel chloride, It will be understood that, from time to time, a mixture of nickel fluoborate and nickel sulfate, it is necessary to replenish the bath to replace b0 and a mixture of nickel sulfate, nickel chloride losses due to cathodic processes, drag-out, and and nickel fiuoborate, said bath also containing, to other causes, in order to maintain the conin solution, not more than about 1.5% of at least centrations of the added compounds, etc. in opone brightener selected from the group consistti r ortions, ing of organic sulfonamides, sulfonimides, and

TABLE III T gunent P N-bencyl-2-methyl quinolinium 1 s00 40 75 to 160... 1ms.2- 10 to l ggggg g j o-benzoyl sullimide-2. N benzyl-3- nethyl isoquiuolin- 2 100 to 300. Oto sat '15 to 60- M05 ttfi fifiigfigigfii acids 3 to N bcnz y1-2-chloro pyridinium 3 100 to 200 200 to 100 40 to 140.. moi-5-. 4 mm.{ fiigfit fgffi gi p-toluene sulfonamidel. N-4 -nitrobenzyl pyridinium chlo- 4 300 60 40 $041?" itifigggtittiimide l to 2.

o-benzoyl sulfimide--l to 3. N-benryl-Z-methyl quinolinium 5 225 501:075 4o 10 to 160... 2.5mmnew.-.{ ggggg;,,g;; g,

o-benzoyl sulfimide2.

sulfonic acids, and, in addition, about 0.003 to 0.04 gram per liter of a'bath-soluble compound in accordance with the formula where A is an anion of a Water-soluble acid, H. is halogen, R is a member selected from the group consisting of halogen, nitro, methyl and fluoromethyl groups, Z is a member selected from the group consisting of hydrogen, methyl and ethyl, and a: and y are each zero to 2.

5. A bath for the electrodeposition of bright nickel comprising an aqueous acidic solution of a material selected from the group consisting of nickel chloride, nickel sulfate, nickel fluoborate, a mixture of nickel chloride and nickel sulfate, a mixture of nickel fiuoborate and nickel chloride, a mixture of nickel fluoborate and nickel sulfate, and a mixture of nickel sulfate, nickel chloride and nickel fluoborate, said bath also containing, in solution, not more than about of at least one brightener selected from the group consisting of organic sulfonamides, sulfonimides, and sulfonic acids, and, in addition, about 0.003 to 0.04 gram per liter of a bath-soluble compound in accordance with the formula where A is selected from the group consisting of chlorine and bromine, R is methyl and a: is zero to 2.

6. A bath for the electrodeposition of bright nickel comprising an aqueous acid solution of a material selected from the group consisting of nickel chloride, nickel sulfate, nickel fluoborate, a mixture of nickel chloride and nickel sulfate, a mixture of nickel fluoborate and nickel chloride, a mixture of nickel fiuoborate and nickel sulfate, and a mixture of nickel sulfate, nickel chloride and nickel fluoborate, said bath also containing, in solution, not more than about 0.5% of at least one brightener selected from the group consisting of organic sulfonamides, sulfonimides, and sulfonic acids, and, in addition, about 0.003 to 0.04 gram per liter of a bath-soluble compound in accordance with the formula where A is an anion of a water-soluble acid, R is halogen, R is a member selected from the group consisting of halogen, nitro, methyl and fluoromethyl groups, and a: and 'J are each zero to 2.

'7. A method of electrodepositing nickel to obtain a fine-grained, ductile deposit of high brilliance which comprises electrolyzing an aqueous acidic solution of at least one nickel salt, said bath also containing, in solution, not more than about 1.5% of at least one brightener selected from the group consisting of organic sulfonamides, sulfonimides, and sulfonic acids, and, in addition, about .003 to .08 gram/liter of a bathsoluble compound in accordance with the formula where v l N I represents a compound of the quinoline series selected from the group consisting of quinoline, isoquinoline and C-methyl and ethyl homologues thereof, A is an anion of a Water-soluble acid, R is halogen, R is a member selected from the group consisting of halogen, nitro, methyl and fluoromethyl groups, Z is a member selected from the group consisting of hydrogen, methyl and ethyl, and a: and y are each zero to 2.

8. A method of electrodepositing nickel to obtain a fine-grained, ductile deposit of high brilliance which comprises electrolyzing an aqueous acidic solution of a material selected from the group consisting of nickel chloride, nickel sulfate, nickel fluoborate, a mixture of nickel chloride and nickel sulfate, a mixture of nickel fluoroborate and nickel chloride, a mixture of nickel fluoborate and nickel sulfate, and a mixture of nickel sulfate, nickel chloride and nickel fluoborate, said bath also containing, in solution, not more than about 1.5% of at least one brightener selected from the group consisting of organic sulfonamides, sulfonimides, and sulfonic acids, and, in addition, about 0.005 to 0.04 gram per liter of a bath-soluble compound in accordance with the formula where A is an anion of a water-soluble acid, R is halogen, R is a member selected from the group consisting of halogen, nitro, methyl and fluoromethyl groups, and m and y are each zero to 2.

9. In a bath for the electrodeposition of bright nickel comprising an aqueous acidic solution of a material selected from the group consisting of nickel chloride, nickel sulfate, nickel fluoborate, a mixture of nickel chloride and nickel sulfate, a mixture of nickel fluoborate and nickel chloride, a mixture of nickel fluoborate and nickel sulfate, and a mixture of nickel sulfate, nickel chloride and nickel fluoborate, an additive for use in an amount of about .003 to .08 gram per liter in combination with at least one brightener selected from the group consisting of organic sulfonamides, sulfonimides and sulfonic acids in an amount of not more than about 1.5% in said bath, said additive consisting of a compound having the formula:

where I I a represents a compound of the quinoline series selected from the group consisting of quinoline,

isoquinoline and C-methyl and ethyl homologues thereof, A is an anion of a water-soluble acid, R is halogen, R is a member selected from the group consisting of halogen, nitro, methyl and fiuoromethyl groups, and a: and y are each zero to 2.

10. An additive for an aqueous acidic solution of nickel salts and at least one brightener selected from the group consisting of sulfonamides, sulfonimides and sulfonic acids in an amount of not more than about 1.5% in combination with said additive in an amount of about .003 to .08 gram per liter, said additive consisting of a compound having the formula:

-cm-N: t-(R). (Rm 1 V where 10 represents a compound of the quinoline series selected from the group consisting of quinoline, isoquinoline and C-methyl and ethyl homologues thereof, A is an anion of a water-soluble acid, R is a halogen, R is a member selected from the group consisting of halogen, nitro, methyl and fluoromethyl groups, and :1: and y are each zero to 2.

HENRY BROWN.

LEROY B. HIGH.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,315,802 Lind Apr. 6, 1943 2,513,280 Brown July 4, 1950 OTHER REFERENCES Raub et a1., Metal Finishing, August 1940, pp. 429-32.

Industrial and Engineering Chemistry, vol. 33, N0. 12 (Dec. 1941), Pp. 1546-48. 

1. A BATH FOR THE ELECTRODEPOSITION OF BRIGHT NICKEL COMPRISING AN AQUEOUS ACIDIC SOLUTION OF A MATERIAL SELECTED FROM THE GROUP CONSISTING OF NICKEL CHLORIDE, NICKEL SULFATE, NICKEL FLUOBORATE, A MIXTURE OF NICKEL CHLORIDE AND NICKEL SULFATE, A MIXTURE OF NICKEL FLUOBORATE AND NICKEL CHLORIDE, A MIXTURE OF NICKEL FLUOBORATE AND NICKEL SULFATE, AND A MIXTURE OF NICKEL SULFATE, NICKEL CHLORIDE AND NICKEL FLUOBORATE, SAID BATH ALSO CONTAINING, IN SOLUTION, NOT MORE THAN ABOUT 1.5% OF AT LEAST ONE BRIGHTENER SELECTED FROM THE GROUP CONSISTING OF ORGANIC SULFONAMIDES, SULFONIMIDES, AND SULFONIC ACIDS, AND, IN ADDITION, ABOUT 0.003 TO 0.08 GRAM PER LITE OF A BATH-SOLUBLE COMPOUND IN ACCORDANCE WITH THE FORMULA 